A conventional image processing apparatus disclosed detects whether a target pixel is a “black edge” and detects whether a target pixel is a “white edge”. The black edge indicates that the target pixel is a black pixel and that density in boundary between the target pixel and an peripheral pixel changes from white to black. The white edge indicates that the target pixel is a white pixel and density in boundary between the target pixel and an peripheral pixel changes from black to white. When the target pixel is the black edge, the image processing apparatus changes the multilevel of the target pixel to its maximum value (level representing complete black). When the target pixel is the white edge, the image processing apparatus changes the multilevel of the target pixel to its minimum value (level representing complete white).